Method of treating heavier hydrocarbons.



S. SCHWARTZ.

METHOD OF TREATING HEAVIER HYD ROCARBONS. APPLICATION FILED-MAY 10, 1911- Patent/ed Nov. 27,1911

. the pressures oils is introduced into STEPHEN scrrvvAETz, 0E

rETEoLEUM rEocEss COMPANY, TION or W sconsin.

MILWAUKEE, WISCONSIN, ASSIGNOB, TO JENKINS 0F MILWAUKEE, WISCQNSIN, A CORPORA- METI-IOD 0F TBEATIITIG HEAVIER HYDROCARBONS.

To all whom it may concern:

Be it known that I, STEPHEN SCHWARTZ, residin at Milwaukee, 'in the county of Milwau cc and State of Wisconsin, have invented a new and useful Improvement in Methods. of Treating Heavier Hydrocarbons.

This invention is for a method and apparatus for treating heavier hydrocarbons such as petroleum oils whereby a condensable, light oil such as gasolene may be obtained therefrom.

My invention relates more particularly to improvements in the production of light oils from heavier oils by cracking as the result of the combined action of heat and pressure on the vapor of the heavy oil.

The principal objects of my present invention are to increase the yield and quality of light oil obtained, to reduce the amount of permanent gases formed, to reduce the percentage of heavy oils in the light oil, to increase the capacity of the apparatus at present employed and generally to improve the production of light oils from heavy oils .by means of the cracking process.

In certain cases the vapor of the heavy the cracking chamber as vapor and in other cases the liquid and vapor. are present simultaneously in the cracking chamber, the liquid being heated to supply the vapor and at the same time generate the'necessary pressure. In the latter case there is an interdependence between the vapor pressure and temperature, increasing temperature being accompanied by an increase in pressure. 7

Where both liquid and vapor are present it is necessary to heat the body of heavy oil to betweent550 and 1000 degrees Fahren-' heit to produce the vapor pressure required to vaporize the heavy oil under the pressure required for cracking the heavy oil .vapor to form the vapor of gasolene or other light that the tem-;

oils. I have found, however, perature at which the highest percentage of gasolene or other light' oils is obtained from the vapor of the heavy oil is lower than the temperature at which the heavy hydrocarbons vaporize or-boil tg generate desired for the cracking of the vapor.

. If the vapor of the heavy oil is cooled Specification of Letters Patent.

the heavy Patented Nov. 2%, 1110152.

Application filed MaylO, 1917. Serial No. 167,711.

crackbelow that temperature before any ing occurred, condensation will occur. however, perature of the vapor may be lowered without producing condensation since the vapor pressure of the lighter oils is greater for any given temperature than it is for the heavier oils.

I have found that close to the surface of oil in the still the temperature is usually lower than that of the oil below it or ofthe vapors and gases adjacent the top of the still, which is possible since the vapor is largely cracked at that point.

This drop in temperature close to the surface of the heavy oil indicates that an endothermic chemical action is taking place at that point and this chemical reaction must be the breaking up or cracking of the molecules of the vapor of the heavy oil. This temperature difference is not con stant in all cases but I have found that at a certain height above the surface of the heavy oil (in one apparatus employed this height was from one-third to one-quarter cracking has taken place the temofrthe height of the top of the still above lower than the temperature of the liquid oil.

I have found that in this cool zone the percentage of fixed gases is very slight and that if the vapor is withdrawn therefrom a larger yield of light oils is obtained than is otherwise the case If the vapor is withdrawn from a higher part of the space above the heavy oil it 'is found to contain a higher percentage of permanent gases which are not desired.

As the point, of withdrawal is raised from the surface of the heavy oil to the top of the vaporizing chamber the density of the gases withdrawn decreases. This appears to be due in part to a progressive breaking up of the molecules of the vapor given 0 by the heavy oil, and in part to a Stratification due to the difi'erent densities of the various gases. of methane (CH and heptane vapor (G,H boiling point 98 (3.), for instance bein about 1:6.

I Trave found that it is advantageous to produce artificially a still further reduction The ratio of the densities has the further effect of first, condensing;

in part at least, any uncracked vapor or the vapor of oils having a higher boiling point than that desired, which may still remain in the cool zone so that these constitutents will largely be returned in liquid drops to the mainbody of liquid for re-' distlllation, and, second, checking, if not stopping, the further disintegration of the molecules of the light oils into permanent gases. In this way the presence of heavy oils on the one hand and permanent gases on the other hand is largely eliminated. The result is to obtain a high yield of a product having a high percentage of hydrocarbons having boil1ng points between the most desirable limits say 95 to 270 degrees Fahrenheit. I

Another advantage of this further reduction in temperature of the cool zone is that it enables the temperature of the liquid oil to be raised, without producing disadvantageous results, so that the .production of vapor from the heavy oil and. the subsequent cracking of that vapor are accelerated. The pressure is, of course, correspondingly raised which also aids the cracking process. I

The production of excessive quantities of permanent gases from the light oil vapor formed which would normally result from the increased temperature and pressure is the cool zon fimevented by the cooling of the vapor in This temperature reduction may be produced by cooling the upper part of the still by exposure to the atmosphere .or to artificial air currents or by cooling the vapors in other ways, but I prefer to' cause the cooling medium to act on the zone which is naturally cooler than the other parts of the vapor space as that is the point at which the vapors contain a maximum amount of light oil vapors.

' As the mere heating of the heavy oil under pressure produces little light oil, and appears to aid the production of carbon, I prefer that the volume of oil in the still should be small relativelyto the vaporizing 9 area, and that the oil should be kept in constant 'circulationto bring each part to the vaporizing surface ,as rapidly and as frequently as possible.

Further if the heavy oil is passed slowly over the heated portions of the still, it is liable to be cracked too fine,'-with--the resulting release of a large proportion of permanent gases, and the simultaneous deposit of carbon. I prefer therefore to circulate the heavy oil positively at such a greatly restrict, if not practically prevent theformation of carbon.

It is particularly advantageous to circulate the oil when the temperature of the oil israised above that normally employed to produce more rapid vaporization other efiects as above described.

Other features of novelty, advantages and capabilities will become apparent from the detailed description of the process and the apparatus for carrying it out illustrated in the accompanying drawings in which:

Figure 1 is a diagrammatic view of an apparatus designed for carrying out my improved method;

Fig. 2 is a vertical transverse section of the cooling apparatus and barrel of the still Fig. 3 is a section on the line 3'3 of Fig. 2; and F Fig. 4 is a section on the line H of In the drawings,heavier hydrocarbon is and pumped from the source of its supply through the feed pipe 1, in which is the check valve 2, control valve 2, and through the inlet pipe 3 terminating in a downwardly directed portion 4 inside the still. The still comprises a strongly reinforced tank or barrel 4:, having depending legs 5 and 6, connected by a series of tubes 7 which slopeupward, as shown.

The rear or lower leg of the boiler comprises an enlarged chamber 5 connected to the barrel 4 by a circulatory passageway 8, in which is mounted a propeller 9 upon the shaft 10, passing out through the barrel through stufling box 13, and equipped at its top with a bevel gear 14, in mesh with which is a bevel gear 15 upon a power shaft 16, the bevel gears l4 and 15 being preferably incased in the housing 17.

Below the still, comprising the barrel 4, legs 5 and 6 and' tubes 7, supporting and inclosing this construction, is arranged a fire box of suitable construction arranged so that the products of combustion sweep upwardly and backwardly along around the 7 tubes.

around or back through the barrel 4 down,

leg 5, up through the boiler tubes, through leg 6 and back into the barrel again.

the pressure (ill adjustable pressure relief valve naaasse I A. level indicator 24 is provided which maybe arranged to control automatically the flow of heavy oil into the still.

Suspended from the top of the barrel 4 is a gas and vapor collector, comprising a large, tubular container 30, perforated at, itsbottom and sides (as indicated in Fig. 2) the interior being in communication with the pipe 32, which is telescopically connected to the cylinder 33 mounted on top of the barrel 4. This cylinder is connected to an 39-, such valves being well known in the art, and no detailed showing thereof being necessary.

From the pressure relief valve the gases and vapor flow through the pipe 34 to the expansion chamber 35 and thence through relief valve 36 and pipe 37 to a condenser 38, from which gasolene and other light by-products may bedrawn.

The gas and vapor collector is of double walled construction comprising an inner wall 40 and an outer wall 41 between which extend a series of open-ended tubes 42 which allow vapor from the still to. enter the collector. The pipe 32 is similarly double walled so that water or other cooling medium may be forced between the walls 40 and 41 of the collector. In order that circulation may be efiected, partitions are arranged between the walls along the upper side of the collector and these partitions are extended between the walls of the pipe 32 on each side thereof.

It is to be particularly noted that the collector 30 is arranged quite near to the level of theliquid in the barrel 4 and preferably in the coolest part of the vapor zone of the still. As theproper location of the collector depends in part on the nature of the oil used as well as on the temperaturesand pressure employed, the collector is arranged so that it can be raised and lowered in the still. 7 For this purpose the pipe 32 is mounted on a piston 42 adapted to slide to and fro in the cylinder 33. ln'order to allow of this sliding movement of the pipe 32, sliding con-l nections are provided between the pipe 32 Y and the inlet and outlet. pipes 47 and'48 for the cooling medium. These sliding connections comprise two pipes 43 and "44 having communication with the spaces between the walls of the pipe 32 on either side of the partition 50, and carrying stuiiing boxes 45 the ends of the pipes' and 46 for receiving 47 and 48. The piston with the collector and other parts is raised and lowered by means of the tube 51 which passes through a stuffing box 52 at the top of the cylinder 33 so that it may be clamped in any desired position by means of set-screws 53 carried by the bracket 54. p 7

This tube is closed at its upper end but is provided intermediate its ends with an applace continuously erture 56 through which the vapor from the still can pass into the pipe leading to the pressure relief valve 39.

in operation, the liquid contents of the still are rapidly circulated around through the barrel, depending legs, and tubes of the apparatus while a brisk fire is maintained therebeneath. The result will be the release of gaseous and vaporous. products and the generation of pressure in the apparatus, evolved gases and vapors collecting in the space barrel 4, wherein they will disintegrate or crack progressively and at the same time tend to arrange themselves at least tempo rarily according to their densities--that is to say, the lighter gases and vapors will take position near the top of the barrel 4 and the heavier gases and vapors collect below them, so that the average density of the gases and vapors at different levels will be different.

The temperature of the reaction may, of course, be controlled by controlling the fire in the fire-box. The pressure in the apparatus is controlled by the adjustable pressure relief valve 39, which is set to maintain the pressure in the apparatus at a point which, in combination with the temperature and the time of treatment, will result in the most efiicient transformation and conversion of. the heavier hydrocarbons being treated into the desired product. There is no defi nite temperature and pressure which will give the best results for all oils and the conditions must be adjusted for the particular oil used. The evolved gases and vapors un-' der whatever pressure the pressure relief valve 39 is set for, are selectively tapped by means of the gasand vapor collector 30, which is preferably set at such a level in the barrel 4 that the heavy oil vapor has largely broken up into light oil vapor but very llttle of the latter has broken up further to form permanent gases such as methane and hydrogen, which will naturally tend to form and collect near thetop of the barrel 4. The cool outer wall 41 of the collector 30 lowers the temperature of the surrounding vapors thereby condensing in part at least, any vapor of heavy oil which has not been cracked and at the same time checks further cracking of the gasolene vapor already formed. Condensation of heavy oil vapor also takes place in part within the collector 30 and the tube 32.

llf the pressure operate at 200 pounds, a constant pressure of approximately 200 pounds will be maintained in the apparatus, and the transformations which will occur by reason of the controlled temperature and pressure, will take in the still, new heavier hydrocarbons being supplied as required through feed pipe 1 to maintain a constant relief 'valve 39 is set to 1 abovethe constant liquid level in the llllll low pressure of say,

pressure relief valve 36,

25 illustrated its use,

I 85 vapor, and which further liquid level in the barrel 4 as that which preceded it is converted into light oil. In actual operation, the entire process occurs smoothly and quietly, the oil flowing rapidly 5 around and around through the apparatus,

and liquefied in a common and well known manner. By means of the positive circulatory system, the liquid may be made to circulate at any desired speed, absolutely preventing its being suddenly heated or over-heated at any point, no matter how hot the fire may be, which practically prevents the deposit of carbon.

Having thus described my invention and what I claim as new and desire to secure by Letters Patent is:

1. The process of treating heavy oils to obtain light oils therefrom comprising heating the heavy oils under pressure and there so byproducing a vapor zone having different temperatures in different parts thereof, withdrawing the vapor from said zone at a point having a lower temperature than another part of said zone and condensing such includes artificlally lowering the temperature of such cool zone.

2. The method of treating heavier hydrosimultaneously through a chamber and heating devices in succession, maintaining pressure in the still, applying heat to said heating devices, drawing off through an artificially cooled collector evolved gases and va-, pors of greater average density than the lightest produced in the chamber.

3. The method of treating heavier hydrocarbons which consists in causing the entire body of the same to circulate simultaneously through a chamber and heating devices in succession, applying heat to said heating de-L vices, drawing off selectively from said chamber through adjustable artificially cooled means evolved gases and vapors of greater average density than the lightest produced in the chamber.

The method of treating heavier hydrocarbons to obtain-light oils therefrom which consists in heating the heavy hydrocarbons under pressure ina still to form vapors and gases in the still of different densities, with-' drawing the vapors in the still through an artificially cooled collecting device from a point intermediate the ends, of said still and at a level above the liquid most conducive to a complete removal of the condensable vapors and below the top of the chamber substantially as shown and described.

In-Witness whereof, I hereunto subscribe MARY B. Fox, HENRY J. SToLz.

my name to this specificationin the presence v 

